zimmerman. Charged more than a year ago in the shooting death of trayvon martin. Jury selection begins today and questions about race likely to play a big role in that process. Abc's matt gutman is covering the trial from sanford, florida. Good morning, matt. Reporter: Good morning, george. In just a couple of minutes some 500 jurors will begin marching into the building behind me. They'll start by filling out a questionnaire specifically designed for this trial but more than questions about what they feel about race or guns, legal experts tell us what may matter most is how they look. This morning, george zimmerman will be back in this florida courtroom facing the potential jurors who could soon be asked to decide his fate. In just a few hours prosecutors and defense attorney will begin grilling the 500 potential jurors in an attempt to find out feelings about self-defense and guns and race. You're going to see a judge that is on ultra alert for the defense trying to exclude jurors solely based on their race. Reporter: Zimmerman who is a white hispanic shot and killed trayvon martin, a black teenager during a scuffle on february 26th, 2012. Prosecutors have charged him with second degree murder. Zimmerman says he was only defending himself and pleaded not guilty. Since that night, the case has polarized this small florida community with protests and rallies seizing sanford, even drawing the notice of the president. If I had a son he'd look like trayvon. Reporter: Late sunday those protests returned. All: The whole system is guilty. Reporter: But the tension never left. He appeared in court wearing a bulletproof vest. This morning we're learning martin's mother says she has been the target of death threats. People have been threatening talking about your kids and family members and specifically by name? Yes, yes. Reporter: Ben krump is the family's attorney. You called it the civil rights trial of the century. The whole world is watching to see how far america has advanced in the matters of equal justice. Does everybody in america get equal justice or just certain people? Reporter: Which is one of the reasons the composition of this jury will be so important. Another reason we're going to see a lot of legal wrangling over what this jury looks like and whittling that jury pool down from 500 to 6 could take weeks. Robin? Matt, thank you. That's why we brought back dan abrams to talk just about the election. A lot of people think when it's a highly publicized case and hard to see the jury. Not really the case. It's going to be tough but they'll find a jury. These don't have to be jurors who know nothing, have never heard of the case. These have to be jurors who haven't developed opinions about the case. As a result you'll have people who likely don't know a lot about it. Haven't been following earth enclosely. Probably find some who haven't followed it at all. Once you get through a lot of people and it'll take a little longer but you'll be able to find a jury in the case. Each side, what are they looking for? That's right. The one issue that no one will admit they're looking at is race. Both sides will look very closely at race and this is going to be the reverse of what you typically see in a case because here the defense is going to be the one who is going to typically want white male nra supporting prospective jurors. The prosecution is going to want the opposite which is unusual to see in a case like this but they'll be listening very, very closely to the answers, reading these questionnaires really closely to try and see nuances, little things in there about these jurors that they say, you know what, this tells me that this person is this or that. A lot of information that's come out lately. Has that helped either side? A lot has come out that has helped george zimmerman since the initial attention on this case. The injuries that he suffered, some questions that have been raised and so this is not an easy case for prosecutors. Not at all and a lot of people will be watching starting today. All right, dan, thanks very

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